US 7,354,694 B1
Styryl dye
Chiaki Kasada, Okayama (Japan); Toshio Kawata, Okayama (Japan); Kentaro Yano, Okayama (Japan); and Shigeo Yasui, Okayama (Japan)
Assigned to Kabushiki Kaisha Hayashibara Seibutsu Kagaku Kenkyuko, Okayama (Japan)
Appl. No. 9/890,711
PCT Filed Nov. 24, 2000, PCT No. PCT/JP00/08298
§ 371(c)(1), (2), (4) Date Aug. 02, 2001,
PCT Pub. No. WO01/40382, PCT Pub. Date Jun. 07, 2001.
Claims priority of application No. 11-343211 (JP), filed on Dec. 02, 1999.
Int. Cl. G11B 7/24 (2006.01)
U.S. Cl. 430—270.18  [430/270.19; 430/945; 369/283; 428/64.8] 3 Claims
OG exemplary drawing
 
1. In an optical recording medium comprising an organic dye compound which has an absorption maximum at a wavelength of 400 nm or shorter, the improvement wherein the organic dye compound is a styryl dye represented by Formula 1 which substantially absorbs a visible light with a wavelength of around 400 nm, said optical recording medium being constructed so as to record information by using a laser beam with a wavelength of 450 nm or shorter, at a recording level of exceeding 4.7 GB (giga bytes) per one side by forming pits having a pit width of below 0.4 μm/pit and a track pitch of below 0.74 μm when formed into a disk, 12 cm in diameter:

OG Complex Work Unit Drawing
wherein in Formula 1, ø1 represents a heterocycle represented by any one of Formulae 2 to 8; ø2 represents an aromatic ring which has a substituent selected from the group consisting of halogen, cyano, nitro, and carboxy, or heterocycle having one or more nitrogen atoms; R1 represents a hydrogen atom, an aliphatic hydrocarbon group, ether group, acyl group, halogen, or cyano group, and the aliphatic hydrocarbon group, ether group, or acyl group may have a substituent; X− represents as a counter ion an azo organic metal complex ion; and “n” is a number of X− to balance the electric charge in the styryl dye:

OG Complex Work Unit Drawing
throughout Formulae 2 to 7, A represents an optionally substituted monocyclic- or polycyclic-aromatic ring or heterocycle; when A is not present in Formulae 2 to 7, one or more substituents similar to those that are bound to A may be in the position where A is located; throughout Formulae 2 to 8, R2 represents an optionally substituted aliphatic hydrocarbon group and R3 represents a hydrogen or an optionally substituted aliphatic hydrocarbon group which is identical to or different from R2.